Articulated robot with variable posture maintenance capability

Variable Posture-Maintaining Articulated Robot with Spring Balancer and Tension Adjustment for Payload Compensation

This technology is an articulated robot featuring a variable posture-maintaining function that adapts to changes in payload. It compensates for the gravitational torque acting on each link by transmitting tension generated from a spring balancer in the robot's main body to each rotating link via tension wires, with a tension adjustment unit to manage varying loads.

Conventional manual gravity compensation devices are designed for specific payloads, leading to degraded posture maintenance when the weight of the end-effector changes. Conversely, motor-based active compensation methods suffer from complex structures and high costs.

This technology proposes a system that uses a spring balancer with a coil spring and a tension adjustment unit to vary the compensation strength according to the payload. By arranging wires and reference rotating bodies across multiple links, it provides continuous compensation torque based on the angle of each joint. It can be applied to collaborative robots and industrial manipulators, maintaining posture under various load conditions while significantly reducing energy consumption.

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Key Features:

• A tension generation unit installed on the robot body that continuously generates tension for gravity compensation
• A rotating link unit coupled to rotate in the direction of gravity, where loads are generated in the direction of rotation
• A tension wire that transmits tension from the generation unit to the rotating link unit to maintain its rotational position
• A tension adjustment unit that regulates the magnitude of tension and an auxiliary torque compensation unit that provides supplemental compensation torque

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This invention was developed with support from the Ministry of Trade, Industry and Energy for the development of a rail-less mobile welding robot to implement high-precision laser welding processes within LNG cargo tanks.